JP6928009B2 - Sheet core material - Google Patents

Description

The present invention relates to a seat core material for an automobile seat.

In recent years, as a seat core material for an automobile seat, a seat core material in which a foam particle molded body and a frame member are integrated, in which a frame member made of metal or the like is embedded inside the foam particle molded body, has been used. There is. The frame member is embedded in the foamed particle molded body as a member for attaching to the vehicle body, a member for reinforcing at the time of a collision, and the like.

The sheet core material in which the frame member is embedded in the foamed particle molded body is manufactured, for example, as follows. First, the annular frame member is arranged at a predetermined position in the mold. The foamed particles are then filled in the mold, and the foamed particles are fused by heating. That is, the sheet core material is manufactured by integrally molding the frame member and the foamed particles.

In addition, since the foamed particle molded product generally shrinks after in-mold molding, the shape of the foamed particle molded product is stable at a size that is shrunk rather than the mold size.

When the foamed particle molded body having such shrinkage characteristics and the annular frame member are integrally molded, it is mainly due to the difference between the shrinkage rate of the foamed particle molded body and the shrinkage rate of the annular frame member. In some cases, the annular frame member itself was deformed due to the shrinkage of the foamed particle molded product, and the sheet core material was warped. Then, the seat core material cannot obtain the desired dimensional accuracy, and there is a problem that the mounting accuracy of the seat core material on the vehicle is lowered.

As a measure to solve these problems in the seat core material of the automobile seat, a divided space is provided in the foamed particle molded body so that the annular frame member is exposed, and the foamed particle molding is independently performed by the divided space. A method of stabilizing the dimensions by contracting the body has been proposed (see, for example, Patent Document 1).

International Publication WO2016 / 152530

According to the proposal of Patent Document 1, since the foamed particle molded product has a completely divided structure, the foamed particle molded product having each divided structure can shrink independently. However, the sheet core material of Patent Document 1 lacks an overall sense of unity, and has a problem that the sheet core material bends or deforms during handling.

The present invention has been made to solve the above problems, and even if the frame member is embedded in the foamed particle molded body and the foamed particle molded body and the frame member are integrated, the foamed particle molded body is deformed. It is an object of the present invention to provide a sheet core material having a sense of unity and strength, which is extremely excellent in dimensional accuracy of a foamed particle molded body.

The present invention provides the sheet core material described below.
<1> A vehicle seat core material composed of a thermoplastic resin foamed particle molded body and a frame member embedded in the peripheral portion thereof, and the foamed particle molded body is on the rear side from the central portion in the front-rear direction. In the range of, there are two or more lightening portions, and in the continuous portion between the lightening portions or in the region up to 100 mm or less on the front side of the continuous portion, along the vehicle width direction of the foamed particle molded product. , A sheet core material provided with penetrating or non-penetrating slits, wherein both ends of the slits in the longitudinal direction are closed.
<2> The sheet core material according to <1>, wherein the opening area of the slit is 5% or less with respect to the projected area of the foamed particle molded body in the top view when the sheet core material is attached. ..
<3> The sheet core material according to <1> or <2>, wherein the frame member is annular, and the frame member is embedded in a peripheral edge of the thermoplastic resin foamed particle molded product.
<4> The foamed particle molded product has two or more of the continuous portions, and the foamed particle molded product has the slits in each of the regions up to 100 mm in front of the two or more continuous portions. The sheet core material according to any one of <1> to <3>, wherein the slits are arranged so as to form an intermittent portion that is intermittent in the vehicle width direction.
<5> The sheet core material according to <4>, wherein auxiliary slits are formed in the vertical direction of the foamed particle molded body on the front side of the intermittent portion in parallel with the slits.

The sheet core material of the present invention has extremely excellent dimensional accuracy and has a sense of unity and strength as a sheet core material even if an annular frame member is embedded and integrated in a thermoplastic resin foamed particle molded body. ..

It is a schematic perspective view which shows one Embodiment of the sheet core material of this invention. It is the schematic which shows one Embodiment of the sheet core material of this invention. It is sectional drawing which showed the cross-sectional shape of a slit. (A) is a cross-sectional view in which a slit is provided perpendicular to the vertical direction when the sheet core material is attached, and (B) is a parallelogram in which the cross-sectional shape of the slit is a parallelogram. In (C), the cross-sectional shape of the slit is trapezoidal. It is a schematic diagram which showed the shape of a slit, (A) to (C) show embodiment which formed auxiliary slit in the intermittent part where a slit is not formed and arranged, and (D) is the formation of a slit. An embodiment in which an auxiliary slit is not formed in a non-intermittent portion is shown. (E) and (F) are schematic views showing the shape of the slit of another embodiment. It is the schematic which shows the embodiment which formed the cut part along the side frame part. It is the schematic which shows two lightening part and continuous part.

The sheet core material of the present invention will be described in detail below with reference to the drawings. 1 and 2 are schematic views showing an embodiment of the sheet core material of the present invention.

The sheet core material 1 of the present invention is composed of a thermoplastic resin foamed particle molded body 3 (hereinafter, also referred to as a foamed particle molded body 3) and a frame member 2 embedded in a peripheral portion thereof. The annular frame member 2 includes a front frame portion 21, a rear frame portion 22, and two left and right side frame portions 23 that connect the front frame portion 21 and the rear frame portion 22 to each other. The frame member 2 is formed in a substantially rectangular shape or a substantially square shape in a top view in accordance with the shape of the peripheral edge of the sheet core material 1. Then, two or more lightening portions 7 and a continuous portion 8 between the lightening portions 7 are formed in a range from the central portion to the rear side in the front-rear direction of the foamed particle molded body 3. Further, slits 4 formed in the vertical direction of the foamed particle molded body 3 are formed in the continuous portion 8 or the region on the front side of the continuous portion 8 along the vehicle width direction. Further, the slit 4 has an end portion, and the end portion in the longitudinal direction thereof is closed. The slit 4 is formed as a non-penetrating slit in which the upper or lower portion of the foamed particle molded body 3 is opened, or a slit penetrating in the thickness direction of the foamed particle molded body 3.

The foamed particle molded body 3 can be molded with a thermoplastic resin. Examples of the thermoplastic resin constituting the foamed particle molded body 3 include a polyolefin resin such as a polystyrene resin, a polyethylene resin, and a polypropylene resin, a polyester resin such as polybutylene succinate, polyethylene terephthalate, and polylactic acid, and a polycarbonate. Examples include based resins. Further, a composite resin of a polystyrene resin and a polyolefin resin, a mixture of two or more kinds of the above resins, and the like can be mentioned. Among these, a polyolefin resin or a composite resin of a polystyrene resin and a polyolefin resin is preferable from the viewpoint of light weight and strength. Of these, polyethylene-based resins and polypropylene-based resins are preferable, and polypropylene-based resins are more preferable. Further, since the foamed particle molded product 3 made of a thermoplastic resin containing a crystalline resin such as polyethylene or polypropylene has a large shrinkage rate after molding, the effect according to the present invention can be more easily obtained.

Further, from the viewpoint of the adhesiveness between the urethane material used together as the seat and the seat core material 1, the foamed particles having a multilayer structure are used as the foamed particles made of the above-mentioned thermoplastic resin which is the material of the foamed particle molded body 3. It is preferable to use it. For example, the foamed particle molded body 3 obtained by having a multilayer structure in which the foamed particles have a core layer in a foamed state and a coating layer covering the core layer and a resin having excellent adhesiveness to a urethane material is used for the coating layer. And the adhesiveness between the urethane material and the urethane material can be further improved. As the foamed particles having a multilayer structure, for example, the core layer in the foamed state is composed of a polyolefin-based resin, and the coating layer is composed of a mixed resin of a polyolefin-based resin and a polystyrene-based resin and / or a polyester-based resin. Examples thereof include polyolefin-based resin multilayer foamed particles. Further, it is preferable that the coating layer is composed of a polyolefin resin (A), a polystyrene resin and / or a polyester resin (B), and the weight ratio of A: B is 15:85 to 90:10.

The foamed particle molded body 3 is formed by in-mold molding of the foamed particles of the thermoplastic resin. The foamed particles can be produced by a commonly known method for producing this type of foamed particles. For example, in the method for producing polypropylene-based resin foam particles, first, a surfactant is added to a required amount of dispersion medium (usually water) in a pressure-sensitive airtight container such as an autoclave, if desired, to obtain the resin particles. Disperse. Then, the dispersion medium in which the resin particles are dispersed is stirred under heating, and the foaming agent is press-fitted into the resin particles to impregnate the resin particles with the foaming agent. Then, after holding the inside of the container under heating for a predetermined time to form secondary crystals of the resin particles, the resin particles impregnated with the foaming agent together with the dispersion medium from the inside of the container under high temperature and high pressure conditions are subjected to a low pressure region (usually). It is released under atmospheric pressure) and foamed to obtain foamed particles.

The apparent density of the foamed particle molded product ³ is preferably 0.015 to 0.3 g / cm 3. Further, from the viewpoint of using the sheet core material 1 having excellent strength and light weight, the lower limit of the apparent density of the foamed particle molded body ³ is more preferably 0.025 g / cm 3, and even more preferably 0.03 g / cm ³ . Further, the upper limit of the apparent density of the foamed particle molded product 3 ^{is more preferably 0.1 g / cm 3 and even} more preferably 0.08 g / cm ³ . The lower limit of the apparent density of the case of the foamed bead molded article 3 consisting of a polyolefin resin is preferably ^{0.018g / cm 3, 0.020g / cm} 3 is more preferable. The upper limit of the apparent density of the case of the foamed bead molded article 3 consisting of a polyolefin resin is preferably ^{0.07g / cm 3, 0.06g / cm} 3 is more preferable. The lower the apparent density of the foamed particle molded product 3, the larger the shrinkage amount of the foamed particle molded product 3, so that the effect of the present invention can be easily exhibited.

Further, a plurality of foamed particle molded products 3 having different apparent densities can be combined to form one foamed particle molded product 3. In this case, the average apparent density of the entire foamed particle molded product 3 may be within the above numerical range. The apparent density used here can be obtained by a submersion method in which the foamed particle molded product 3 is submerged and measured.

Examples of the material of the frame member 2 include metals and resins such as iron, aluminum, and copper. From the viewpoint of improving the strength of the sheet core material 1, metal is preferable, and steel is particularly preferable. Further, as the annular frame member 2, any shape such as linear, tubular, rod-shaped, etc. can be used, and among these, a rod-shaped or linear wire material having a diameter of 2 to 8 mm is preferably used. The diameter of the wire material is more preferably 3 to 7 mm.

Further, the wire material preferably has a tensile strength of 200 N / mm ^{2 or more, and more preferably 250 to 1300 N / mm 2} from the viewpoint of improving the strength of the sheet core material 1. The yield point of the wire material ^{is preferably 400 N / mm 2} or more, and more preferably 440 N / mm ² or more. The physical characteristics of the wire material can be measured based on JIS G3532. Further, the annular frame member 2 can be formed in an annular shape by welding or bending the above material.

The frame member 2 does not necessarily have to be formed of only the wire material, and for example, the wire material may be connected to form the frame member 2 by a metal plate or the like. Further, if necessary, a hook portion or the like for fixing to the vehicle may be connected to the plate. The frame member 2 preferably has an annular shape as a basic structure, and more preferably has a substantially rectangular shape or a substantially square shape when viewed from above. It is also possible to bend the sides and short sides and cut out the corners.

The frame member 2 is embedded and integrated inside the foamed particle molded body 3, and is used for improving the strength of the seat core material 1 and attaching it to the vehicle body. As shown in FIG. 2, the seat core material 1 of the present invention is composed of a front frame portion 21, a rear frame portion 22, and left and right side frame portions 23 that connect the front frame portion 21 and the rear frame portion 22 to each other. It is embedded in the foamed particle molded body 3 as an annular frame member 2.

The above-mentioned "buried" means that the frame member 2 is integrated with the foamed particle molded body 3 in the foamed particle molded body 3. For example, not only when the frame member 2 is closely surrounded by the foamed particle molded body 3, but also through a gap (or space) partially or wholly formed around the frame member 2, the frame member 2 Is surrounded by the foamed particle molded body 3. Further, the frame member 2 does not need to have the entire length in the axial direction embedded in the foamed particle molded body 3, and for example, as shown in FIG. 2, a part of the frame member 2 is formed from the foamed particle molded body 3. It may be exposed to the outside. From the viewpoint of the strength of the sheet core material 1, the exposed portion of the frame member 2 (the portion where the frame member 2 is exposed from the foamed particle molded body 3) is 50% or less of the total length of the frame member 2. It is preferably 30% or less, and more preferably 30% or less.

Further, the frame member 2 embedded in the foamed particle molded body 3 moves in a direction substantially perpendicular to both the contraction direction of the foamed particle molded body 3 and the axial direction of the frame member 2. However, it is regulated by the foamed particle molded product 3. Therefore, it is preferable that the frame member 2 is embedded so as to be able to move with respect to the shrinkage of the foamed particle molded body 3. For example, when the contraction force of the foamed particle molded body 3 applied to the frame member 2 acts mainly in the vehicle width direction of the seat core material, the foamed particle molded body 3 is used at a position perpendicular to the vehicle width direction of the frame member 2. It is preferable that the frame member 2 is embedded in the foamed particle molded body 3 in a state where the frame member 2 is sandwiched. Further, it is more preferable that the frame member 2 is supported by the foamed particle molded body 3 from the vertical direction.

Here, the front frame portion 21 in the frame member 2 means a portion of the frame member 2 corresponding to the front portion of the seat on the front side of the automobile when the seat core material 1 is attached to the vehicle of the automobile, and the rear frame portion 22 means a portion of the frame member 2 corresponding to the rear portion of the seat. Further, the vehicle width direction means the left-right direction of the automobile in a state where the seat core material 1 is attached to the vehicle of the automobile, and may be simply referred to as the width direction. Further, the vertical direction means the vertical direction of the automobile in a state where the seat core material 1 is attached to the vehicle of the automobile.

The sheet core material 1 preferably has a shape of a substantially rectangular shape or a substantially square shape when viewed from above, but a shape as shown in FIG. 1 in which the front portion is thick and the rear portion is thin is used. Is preferable. In such a sheet core material 1, the volume of the foamed particle molded body 3 is larger in the seated portion on the front frame portion 21 side than in the seated portion on the rear frame portion 22 side, so that the shrinkage amount of the foamed particle molded body 3 is large. The seating portion on the front frame portion 21 side is larger than the seating portion on the rear frame portion 22 side. Further, in the front frame portion 21, the frame member 2 is unevenly embedded on the lower surface side of the seat core material 1 from the viewpoint of attachment to the vehicle. When the frame member 2 is arranged on the sheet core material 1 in this way, the central portion of the foamed particle molded body 3 on the rear frame portion 22 side is the foamed particle molded body 3 on the front frame portion 21 side after being taken out from the mold. As the rear frame portion 22 is contracted, it is pulled particularly toward the front side, and the rear frame portion 22 side is easily deformed so as to have a V shape as a whole. For example, in the foamed particle molded body 3 on the rear frame portion 22 side, the foamed particle molded body 3 on the width direction end side is deformed toward the front. Further, the foamed particle molded body 3 in the central portion is deformed toward the front larger than the end portion. Therefore, as a whole, the sheet core material 1 is deformed so as to have a V shape when viewed from above. Further, in the thick front frame portion 21, if the frame member 2 is embedded at a position biased in the thickness direction, the direction of contraction becomes three-dimensional, and the deformation becomes more complicated. In the sheet core material 1 of the present invention, in particular, the thickness Tf of the front end portion of the sheet core material 1 and the thickness Tr of the rear end portion of the sheet core material 1 are Tr × 1.5 <Tf. Is preferable, and Tr × 1.7 <Tf is more preferable.

In the sheet core material 1 of the present invention, at least two or more lightening portions 7 are formed in a range from the central portion to the rear side of the foamed particle molded body 3. Specifically, the lightening portion 7 is formed between the side frame portions 23 at both ends on the rear frame 22 portion side from the center portion in the front-rear direction of the foamed particle molded body 3. The lightening portion 7 may be formed thinner than the thickness of the surrounding foamed particle molded body 3, but the lightening portion 7 penetrating from the upper surface to the lower surface of the foamed particle molded body 3 is formed as a through hole. Is preferable. Further, a continuous portion 8 is formed as a foamed particle molded body 3 portion between two or more lightening portions 7, and the continuous portion 8 has a rear frame portion 22 side and a front frame portion 21 side continuous in the front-rear direction. As such, it is formed adjacent to the lightening portion 7. The lightening portion 7 is formed in the foamed particle molded body 3 for, for example, meat stealing and attachment of parts and the like.

The shape of the lightening portion 7 is not particularly limited, and two or more lightening portions 7 may have different shapes. Further, as shown in FIG. 7, when the ends of the two lightening portions 7 in the front-rear direction are provided at different positions, the frontmost portion and the rearmost portion of the two lightening portions 7 are referred to. The region in the two front and rear lines extended along the width direction is the continuous portion 8. Further, the portion sandwiched in the line extending in the front-rear direction with respect to the end end portion of the lightening portion 7 on the continuous portion 8 side sandwiched between the respective lightening portions 7 is referred to as the continuous portion 8. The region is determined with reference to the continuous portion 8 determined by the line segment.

For example, when two lightening portions 7 are formed between the side frame portions 23, one continuous portion 8 sandwiched between the lightening portions 7 is provided. Further, when three lightening portions 7 are formed, two continuous portions 8 are similarly provided.

The lightening portion 7 is preferably formed between the side frame portions 23 and between the rear frame 22 portion and the front frame 21 portion, and preferably has a space penetrating from the upper surface to the lower surface, but the rear frame portion The shape may be such that the through space is continuous on the outer side of the 22 or the side frame 23. For example, if the corners of both ends of the rear side of the sheet core material 1 are hollowed out and two lightening portions 7 are formed at both ends of the sheet core material 1, the continuous portion 8 may be formed. It will be formed on the inner side of the lightening portion 7.

In the continuous portion 8 of the foamed particle molded body 3 in which the rear frame portion 22 side and the front frame portion 21 side are continuous, the influence of the shrinkage of the foamed particle molded body 3 in the front portion is transmitted to the rear side. Become. On the other hand, in the lightening portion 7, the foamed particle molded body 3 is discontinuous in the front-rear direction, so that the influence of shrinkage is not transmitted.

Therefore, in the present invention, a slit 4 formed in the vertical direction of the foamed particle molded body 3 is formed in the continuous portion 8 or the region on the front side of the continuous portion 8 in the width direction. By forming the slit 4 in the continuous portion 8 of the foamed particle molded body 3 or the region on the front side of the continuous portion 8, the influence of the shrinkage force generated on the foamed particle molded body 3 on the front side is alleviated from being transmitted to the rear side. It becomes possible to do. As a result, the deformation of the sheet core material 1 can be effectively suppressed, and the sheet core material 1 can be obtained with excellent dimensional stability while having strength and a sense of unity. The region is a range up to 100 mm or less on the front side of the continuous portion 8, and the upper limit of the range on the front side of the continuous portion 8 of the continuous portion 8 is preferably a range of 80 mm, more preferably a range of 60 mm. .. On the other hand, the region is preferably a range of 3 mm or more on the front side of the continuous portion 8, and more preferably a range of 5 mm or more. It is sufficient that at least the rear end portion of the slit 4 is formed in the above region.

Further, the slit 4 does not necessarily completely block the continuous portion 8 in the front-rear direction, and the width direction length of the slit 4 is 50% or more, preferably 50% or more, based on the width direction length of the continuous portion 8. It is preferably formed with a length of 70% or more. Both ends of the slit 4 in the longitudinal direction are closed, and the slit 4 has at least an end portion.

For example, when the slit 4 is formed in the continuous portion 8 portion sandwiched between the lightening portions 7, the slit 4 is formed leaving a gap between the lightening portion 7 and the end portion of the slit 4. .. In this case, since both ends of the slit 4 are closed, the slit 4 is not continuous with the lightening portion 7, and a gap portion is formed between both ends of the slit 4 and the lightening portion 7.

Further, as shown in FIG. 7, in the case of the continuous portion 8 in which the two lightening portions 7 are formed so as to be displaced in the front-rear direction, the lightening portion 7 is formed on one side and the opposite side in the vehicle width direction. There may be a portion where the lightening portion 7 is not formed on the other side. When the slit 4 is formed in this portion, it is preferable that the slit 4 is formed leaving a gap between at least one end of the slit 4 and the lightening portion 7. Further, on the other side of the slit 4, it is preferable that the slit 4 is formed over the continuous portion 8.

Further, when the slit 4 is formed in the region of the foamed particle molded body 3 portion on the front side of the continuous portion 8, even if both ends of the slit 4 are formed in the above region, one of the slits 4 is formed. The ends may be formed within the range of the region, or both ends of the slit 4 may be formed outside the range of the region, but they are formed over the region and both ends of the region. It is preferably formed at a location outside the range.

When the slit 4 is formed in the front side region of the continuous portion 8, the slit 4 is formed over the continuous portion 8 and an interval of 5 to 100 mm is provided on the front side of the lightening portion 7. It is preferable that the slit 4 is formed. Further, it is preferable that the slit 4 and the lightening portion 7 have a portion that overlaps in the front view. Specifically, it is preferable that the slit 4 is extended by 5 mm or more from the front side region of the continuous portion 8 and the end portion of the slit 4 is formed at a position separated from the region by 5 mm or more in the vehicle width direction. It is more preferably 10 mm or more, and further preferably 20 to 200 mm.

When a plurality of continuous portions 8 are present, the slits 4 may not be formed in all the continuous portions 8 or the corresponding portions on the front side thereof. Further, at least, the slit 4 may be formed in the continuous portion 8 at the position corresponding to the seating portion and the central portion of the foamed particle molded body 3 on the inner side of the sheet core material 1.

Further, the length (m) of the side frame portion 23 of the slit 4 in the longitudinal direction (front-back direction) is not particularly limited, and the length (m) in the front-rear direction is about 60 mm from the slit 4 in which the notch is simply made. Although the slit 4 is taken into consideration, the length (m) in the front-rear direction is preferably 3 to 50 mm from the viewpoint of the strength of the sheet core material 1.

The slit 4 can be formed at a corresponding portion of the foamed particle molded body with a tool such as a cutter immediately after the foamed particles are molded in the mold and before the shrinkage starts. It is also possible to form the slit 4 at the same time as molding the foamed particle molded body 3 by using a molding die configured to form the slit 4. When the slit 4 is formed by a mold, the length of the slit 4 in the front-rear direction is preferably 3 to 40 mm, more preferably 5 to 30 mm. The slit 4 may or may not penetrate the foamed particle molded body 3 as long as the shrinkage can be suppressed. From the viewpoint of more effectively preventing shrinkage, the slit 4 is preferably formed up to a depth of 50% or more of the thickness of the foamed particle molded product 3, and more preferably the foamed particle molded product 3. It is preferable that it is formed up to a depth of 80% or more of the thickness of 3, and it is preferable that it penetrates. When the slit is a bottomed hole, the slit 4 may be opened toward the upper surface or the lower surface.

Further, as shown in FIG. 2, the slit 4 is formed in a region on the front side of the continuous portion 8 when two continuous portions 8 are formed in the foamed particle molded body 3 by the three lightening portions 7. It is preferable to form slits 4 respectively. Further, it is preferable that the slits 4 are formed in the foamed particle molded body 3 intermittently in the width direction.

In this case, for example, as shown in FIGS. 4A to 4D, the two slits 4 are intermittently arranged between the side frame portions 23 in the width direction, so that the slits 4 Intermittent portions 9 are formed between the ends on the inner side in the width direction of the above. Further, the slit 4 is preferably formed in a straight line through the intermittent portion 9.

Here, the slit 4 is formed at least in the continuous portion 8 or the region on the front side of the continuous portion 8, and the formation position of the slit 4 in the width direction is not particularly limited as long as it has an end portion. For example, the end portion of the slit 4 may be in contact with the side frame portion 23, and the side frame portion 23 may be partially exposed. However, from the viewpoint of the strength of the sheet core material 1, there is a foamed particle molded body 3 portion in which the slit 4 is not formed between the lateral end portion in the width direction of the slit 4 and the side frame portion 23. Is preferable.

In the intermittent portion 9, since the sheet core material 1 is connected in the front-rear direction by the foamed particle molded body 3, the intermittent portion 9 improves the sense of unity such as the strength of the sheet core material 1. On the other hand, since the intermittent portion 9 can be said to be the foamed particle molded body 3 portion that connects the front and rear of the sheet core material 1, the shrinkage of the foamed particle molded body 3 becomes a factor that affects the front-rear direction.

Therefore, in the sheet core material 1 of the present invention, as shown in FIGS. 4A to 4C, the front side of the foamed particle molded body 3 portion in which the slit 4 on the width extension of the slit 4 is not formed and / Or an auxiliary slit 6 can be provided on the rear side in the width direction. The auxiliary slit 6 is preferably provided in parallel with the slit 4. Here, "parallel to the slit 4" means that the slit 4 is substantially parallel to the extension in the width direction.

On the other hand, when the slit 4 is formed in the region up to 100 mm or less on the front side of the continuous portion 8 between the lightening portions 7, the front of the portion where the slit 4 is not formed on the extension in the width direction of the slit 4. It is preferable to provide at least one auxiliary slit 6 which penetrates from the upper surface to the lower surface of the foamed particle molded body 3 and is closed at both ends on the side and / or the rear side, adjacent to the slit 4. Further, the auxiliary slit 6 is preferably provided on the front side of the slit 4.

For example, as shown in FIGS. 4A to 4C, three lightening portions 7 are formed in the sheet core material 1, two continuous portions 8 are formed between the lightening portions 7, and two lightening portions 8 are formed. When each slit 4 is formed in the region on the front side of the continuous portion 8, the front side of the intermittent portion 9 which is a portion where the slit 4 is not formed on the extension in the width direction of each slit 4 and / Alternatively, an auxiliary slit 6 penetrating from the upper surface to the lower surface of the foamed particle molded body 3 can be provided adjacent to the slit 4 on the rear side.

Further, it is preferable that the slit 4 and the auxiliary slit 6 have an overlapping portion in the front-rear direction and are formed at adjacent positions on the front side. Further, it is preferable that the slit 4 and the auxiliary slit 6 are formed so as to have a portion in which the slits are parallel to each other. For example, in the case of FIG. 4B, the end portion of the auxiliary slit 6 is located on the outer side of the end portion of the slit 4, and the slits are partially parallel to each other. In particular, when the slit 4 and the auxiliary slit 6 have a portion that overlaps in the front-rear direction, the length of the overlapping portion is preferably 0 to 200 mm, more preferably 10 to 150 mm.

By forming the auxiliary slit 6 in this way, the intermittent portion 9 is closed by the auxiliary slit 6 when viewed from the front-rear direction, so that the influence of the contraction in the front-rear direction can be further reduced.

Further, as described above, when the auxiliary slit 6 is formed, the slit 4 and the auxiliary slit 6 have a structure in which the portion where the slit is not formed is bent. Since this bent portion exerts an elastic force in the front-rear direction due to bending deformation, it is possible to more absorb the contraction force and the impact force applied in the front-rear direction. Since the bent structure becomes more prominent as the overlapping portion becomes longer, the amount of deformation of the sheet core material can be reduced.

On the other hand, when the slit 4 is formed in the continuous portion 8, it penetrates from the upper surface to the lower surface of the foamed particle molded body 3 on the front side of the portion where the slit 4 is not formed on the extension of the slit 4 in the width direction. However, it is preferable to provide an auxiliary slit 6 having both ends closed along the width direction. For example, as shown in FIG. 5 (E), when the slit 4 is formed in the continuous portion 8, the front side of the portion where the slit 4 is not formed on the extension of the slit 4 in the width direction, and the above-mentioned region. It is preferable that at least one auxiliary slit 6 penetrating from the upper surface to the lower surface of the foamed particle molded body 3 is provided. The auxiliary slits 6 may be provided at corresponding locations of the plurality of continuous portions 8, but may also be provided continuously in the width direction. Further, if the auxiliary slit 6 is provided at least on the front side of the portion where the slit is not formed on the extension in the width direction of the slit 4 and in the region, the auxiliary slit 6 extends in the vehicle width direction to the outside of the range of the region. It can also be extended to.

Further, the auxiliary slit 6 may be formed intermittently as shown in FIG. 5 (F). In the example of FIG. 5 (F), the slit 4 is formed in the continuous portion 8 sandwiched between the lightening portions 7, and there is a gap portion between the slit 4 and the lightening portion 7. Although the connection of the continuous portion 8 in the front-rear direction is almost closed by the slit 4, the gap portion, which is the portion on the extension of the slit 4 in the width direction in which the slit is not formed, is connected in the front-rear direction. It is preferable to provide the auxiliary slit 6 in the region on the front side of the gap portion.

As described above, by forming the auxiliary slit 6, the influence of the contraction force transmitted in the front-rear direction at the portion where the slit 4 is not formed on the extension of the slit 4 in the width direction and the intermittent portion 9 can be reduced. The foamed particle molded body 3 on the rear frame portion 22 side is pulled forward as the foamed particle molded body 3 on the front frame portion 21 side shrinks, and the sheet core material 1 is deformed into a V shape as a whole. Can be effectively prevented from doing so. Therefore, it is preferable that the auxiliary slit 6 is formed at least on the inner side of the sheet core material 1 at a portion where the slit 4 is not formed or at the intermittent portion 9.

Further, the auxiliary slit 6 is formed at an adjacent position on the front side of the slit 4, and it is preferable that the slit 4 and the auxiliary slit 6 are formed at a distance of 5 to 100 mm in the front-rear direction. The distance between the auxiliary slit 6 and the adjacent slit 4 in the front-rear direction is more preferably 10 to 70 mm, further preferably 15 to 50 mm, and most preferably 20 to 40 mm. When the interval is within the above range, the dimensional change of the sheet core material 1 is reduced, and the feeling of unity of the sheet core material 1 is excellent.

Further, as shown in FIG. 6, it is preferable that the end portion of the foamed particle molded body 3 in the width direction is provided with a connecting portion 10 having no slits such as a slit 4 and an outer slit described later. .. In the portion where the slit is not formed from the end portion of the foam particle molded body 3 to the outer end portion of the slit with respect to the length (L) in the width direction in the portion where the connecting portion 10 of the foamed particle molded body 3 is located. The ratio (l / L) of the length (l) of the connecting portion 10 in the width direction is preferably in the range of 0.02 to 0.2 per side. In the peripheral edge of the sheet core material 1 shown in FIG. 2, the connecting portions 10 which are the portions where the slits are not formed are formed at two locations on both sides in the width direction, but both portions satisfy the above range. Is preferable.

When (l / L) is within the above range, since there are portions where slits are not formed at both ends in the width direction of the sheet core material 1, the dimensional change of the sheet core material is small, and the sheet core material 1 has a small dimensional change. It will be excellent in strength and sense of unity. Further, the ratio (l / L) is more preferably 0.05 to 0.15.

Specifically, the ratio (l / L) of the length (l) in the width direction of the connecting portion 10 to the length (L) in the width direction at the portion where the connecting portion 10 of the foamed particle molded body 3 is located is specifically. , Can be measured as follows. As shown in FIGS. 2 and 6, a straight line (b1) is drawn in the width direction of the foamed particle molded body 3 at the center portions (a1 and a2) in the front-rear direction at both ends on the outer edge side of the slit 4, and the straight line (b1) portion is drawn. It is a slit 4 forming portion. Then, the length L of the straight line (b1) between both end portions (a1, a2) of the foamed particle molded body 3 is measured. _{On the other hand, the lengths l 1} and l ₂ on the straight line from the three ends (a1, a2) of the foamed particle molded body to both ends (c1, c2) of the slit 4 are set to l, respectively, and (l / L) per side. ) Is calculated.

Further, the forming position of the connecting portion 10 is not particularly limited as long as it is the outer end portion in the width direction of the foamed particle molded body 3, but the rear frame portion 22 is formed from the central portion in the front-rear direction of the foamed particle molded body 3. It is preferably formed in the range up to. By forming the connecting portion 10 at a position from the central portion of the foamed particle molded body 3 to the rear frame portion 22, the strength and the sense of unity of the sheet core material 1 can be improved.

Further, a connecting portion 10 made of a foamed particle molded body 3 is provided on the outer side in the width direction of the lightening portion 7 on the outer side in the width direction of the sheet core material 1, and the connecting portion 10 or the front side thereof has a connecting portion 10. An outer slit penetrating from the upper surface to the lower surface of the foamed particle molded body 3 can be provided in the width direction. Further, it is preferable that the outer side slit is formed on the inner side of the annular frame member 2. The outer slit can be made continuous with the slit 4. The shape and size of the outer slit are preferably the same as those of the slit 4.

The slit 4, the outer slit and the auxiliary slit 6 are 50 to 90% of the length (M) in the front-rear direction at the center of the foamed particle molded body 3 from the end of the foamed particle molded body 3 on the front side. It is preferably formed in a portion of 60 to 80%, and more preferably formed in a portion of 60 to 80%. By forming the slit in the above range, the influence of the contraction force of the foamed particle molded body 3 on the front frame portion 21 side, which is thick and has a relatively large volume, can be effectively alleviated, and the rear side rises easily deformed. The influence on the dimensional change of the portion can be reduced, and the sheet core material 1 can have a sense of unity. Further, it is preferable that the slit 4, the outer slit and the auxiliary slit 6 are provided in a range from the seating portion of the seat core material 1 to the front side of the rising portion on the rear side.

The outer slit and the auxiliary slit 6 have been described as penetrating slits as described above, but similarly to the slit 4, the outer slit and the auxiliary slit 6 are within a range that does not impair the effect of the present invention. It may be non-penetrating. Therefore, the slit 4, the outer slit, and the auxiliary slit 6 may have a portion that does not penetrate in the vertical direction in a part thereof.

Further, the total opening of the slit 4, the slit 4 and the auxiliary slit 6 or the total opening of the slit 4 and the auxiliary slit 6 and the outer slit with respect to the projected area of the foamed particle molded body 3 in the top view of the sheet core material 1. The area is preferably 5% or less. By setting the opening area of the slit to the above range, deformation can be sufficiently prevented, and the sheet core material 1 having a more sense of unity and strength can be obtained. From the above viewpoint, the total opening area of the slit 4, the auxiliary slit 6, and the outer slit is preferably 3% or less. The lower limit of the opening area is approximately 0.5%, preferably 0.7% or more.

Further, in the present invention, as shown in FIG. 3A, the depth direction of the slit 4, the outer slit, and the auxiliary slit 6 or the penetration direction when the slit is penetrated is when the sheet core material 1 is attached. In addition to being formed perpendicular to the vertical direction of the sheet, it can also be formed so as to be inclined with respect to the vertical direction when the sheet core material 1 is attached. Specifically, as the shape of the slit cross section obtained by cutting the slit 4 and the auxiliary slit 6 in the front-rear direction, a parallelogram cross-sectional shape as shown in FIG. 3 (B) and a trapezoid as shown in FIG. 3 (C). The cross-sectional shape of is illustrated. In this way, the depth direction of the slit 4, the outer side slit, and the auxiliary slit 6 is formed so as to be inclined with respect to the vertical direction when the sheet core material 1 is attached, so that the upper surface portion of the sheet core material 1 is formed. It is possible to adjust the opening position and opening area of the slit 4, the outer slit and the auxiliary slit 6.

In particular, by inclining the penetrating direction of the slit 4 and forming the front and rear side walls of the slit 4 substantially in parallel, there is an effect of distributing the force in the vertical direction with respect to the contraction force and the impact force applied in the front-rear direction. Therefore, it can be used more preferably. The penetration direction of the slit 4, the outer slit, and the auxiliary slit 6 refers to a line connecting the center of the slit opening in the front-rear direction with the upper surface and the lower surface. Further, if the cross section orthogonal to the width direction of the slit is trapezoidal, there is an advantage that urethane is easily fixed when the seat core material 1 is used together with urethane to form a seat.

Further, in the sheet core material 1 of the present invention, a notch portion 5 can be formed inside the side frame portion 23 of the foamed particle molded body 3 in the thickness direction and the front-rear direction from the upper surface. The number of cut portions 5 may be one or a plurality of cut portions 5. Further, the formation position of the cut portion 5 may be formed adjacent to the inner side of the side frame portion 23 or may be formed in the central portion. Specifically, for example, as shown in FIGS. 1 and 6, it is preferable to form them in the front-rear direction. The width (length in the left-right direction) of the cut portion 5 is preferably 10 to 30 mm, and the length in the front-rear direction is preferably 50 to 200 mm.

By forming the cut portion 5 together with the slit 4, the shrinkage in the width direction can be alleviated, the deformation of the sheet core material 1 can be further suppressed, and the sheet core material 1 having a sense of unity and strength can be obtained. .. The cut portion 5 is preferably provided up to about 50% or more of the thickness of the foamed particle molded body 3 from the upper surface in the thickness direction of the molded body, and is more preferably provided up to 80% or more. It is preferable, and it is more preferable that it penetrates. Further, the notch 5 can be a combination of a penetrating portion and a non-penetrating portion as long as the above effect is not impaired.

Further, in the sheet core material 1 of the present invention, the weight is reduced in places other than the lightening portion 7, the slit 4, the auxiliary slit 6, and the notch portion 5 as long as the sense of unity and strength, which are the objects of the present invention, are not impaired. A through space or a recess may be formed for connection with other parts or the like.

In the production of the sheet core material 1 of the present embodiment, a molding die in which a convex portion for forming the slit 4 and the auxiliary slit 6 is formed at a position between the side frame portions 23 is used. Then, in a state where the annular frame member 2 is arranged at a predetermined position of the molding mold, the mold is filled with the foamed particles that have been primarily foamed, and then the heating steam is introduced into the mold. As a result, the foamed particles in the mold are heated for secondary foaming, and the surface of the foamed particles is melted to form the foamed particle molded body 3, and the foamed particles are integrated with the annular frame member 2 and obtained by in-mold molding. can. The sheet core material 1 formed under predetermined conditions starts shrinking of the foamed particle molded body 3 from the stage of being removed from the mold, but is foamed by the slit 4 formed by the mold, the outer slit, and the auxiliary slit 6. The influence of shrinkage of the particle molded body 3 is alleviated and deformation is suppressed.

Further, in addition to the method of forming a slit by the above-mentioned mold, the sheet core material 1 is formed by using a conventional mold having no structure for forming the slit 4, the outer side slit and the auxiliary slit 6 in the mold. It is also possible to form the slit 4, the outer slit and the auxiliary slit 6 by a method such as cutting at an early stage after forming and removing the mold from the mold. When the slit is formed by cutting, it is preferably processed within 60 minutes after demolding, more preferably within 30 minutes, and further preferably within 15 minutes.

Hereinafter, the sheet core material of the present invention will be specifically described with reference to Examples. However, the present invention is not limited to the examples.

Example 1
An annular frame member manufactured using an iron wire material with a diameter of 4.5 mm and a tensile strength (JIS G3532 SWM-B) of 500 N / mm ² is used to form an automobile seat seat core material molding die (width direction 1050 mm, front and rear). It was arranged at a predetermined position in a direction of 550 mm and a maximum thickness of 200 mm (thickness of the front end portion of 100 mm, thickness of the rear end portion of 50 mm). Then, polypropylene foam particles (apparent density 0.024 g / cm ³ ) were filled in the mold, and steam heating was performed for insert molding to form a sheet core material having the shape shown in FIG.

For heating by steam, steam was supplied into the mold for 5 seconds with the drain valves of the double-sided mold open, and preheating (exhaust step) was performed. After that, one-sided heating is performed at a pressure 0.08 MPa (G) lower than the molding steam pressure of 0.3 MPa (G), and then one-sided heating is performed from the opposite direction at a pressure 0.04 MPa (G) lower than the molding steam pressure. After that, main heating was performed from both sides with molding steam pressure. After the heating was completed, the pressure was released, air-cooled for 30 seconds, and water-cooled for 240 seconds to obtain a sheet core material. The density of the molded body of the sheet core material was 0.03 g / cm ³ .

The sheet core material 1 is composed of a foamed particle molded body 3 and an annular frame member 2 embedded in a peripheral portion thereof. The annular frame member 2 forms a rectangular annular frame composed of a front frame portion 21, a rear frame portion 22, and two side frame portions 23 that connect the front frame portion 21 and the rear frame portion 22 to each other. Further, in the range from the central portion in the front-rear direction to the rear frame portion 22 of the foamed particle molded body 3, three lightening portions 7 are formed at both end portions and the central portion between the side frame portions 23. Two continuous portions 8 in which the front frame portion 21 and the rear frame portion 22 side are continuous are provided between the lightening portions 7.

Next, within 10 minutes after molding, as shown in FIG. 4A, a rectangular slit 4 having a length of 250 mm in the sheet width direction and a length of 10 mm in the front-rear direction was placed at a position 400 mm from the front portion (from the lightening portion 7). (10 mm front area), from a position 140 mm from the end in the vehicle width direction, a total of two were formed in a straight line, one on each side with a cutter knife in the width direction. Two slits 4 were formed over the region on the front side of the continuous portion 8 sandwiched between the three lightening portions 7. Further, in the intermittent portion 9 between the slits 4 in the central portion of the sheet core material, a rectangular auxiliary slit 6 having a length of 270 mm in the sheet width direction and a length of 10 mm in the front-rear direction is provided at a position 360 mm from the front portion by a cutter knife. Formed. Each slit was arranged so that the central end of the left and right slits 4 and the end of the auxiliary slit 6 were in contact with each other when viewed from the front-rear direction. Therefore, a slit penetrating from the upper surface to the lower surface of the foamed particle molded body 3 is provided on the front side of the continuous portion 8 existing in the portion sandwiched between the lightening portions 7 in the vehicle width direction. Two slits 4 are formed on the front side of the continuous portion 8 in a linear manner in the vehicle width direction of the foamed particle molded body 3, and two slits are formed in an adjacent portion on the front side of the intermittent portion of the slit 4. Auxiliary slits 6 are provided in parallel with 4 in the vehicle width direction.

Example 2
In the same manner as in Example 1, a sheet core material having no slits was formed. Then, within 10 minutes after molding, as shown in FIG. 4B, the foamed particle molded body 3 between the side frame portions 23 has a length of 250 mm in the sheet width direction and a length of 10 mm in the front-rear direction. A total of two rectangular slits 4 were formed on the left and right by a cutter knife from a position 400 mm from the front portion (area on the front side 10 mm from the lightening portion 7) and 140 mm from the end portion in the width direction in the width direction. .. The slit 4 was formed on the front side of the two continuous portions 8 sandwiched between the three lightening portions 7. Further, in the central portion of the foamed particle molded body 3, one rectangular auxiliary slit 6 having a length of 500 mm in the sheet width direction and a length of 10 mm in the front-rear direction was formed at a position 360 mm from the front portion by a cutter knife. Each slit was arranged so that the left and right slits 4 and the central auxiliary slit 6 overlap 135 mm when viewed from the front-rear direction.

Example 3
In the same manner as in Example 1, a sheet core material having no slits was formed. Then, within 10 minutes after molding, as shown in FIG. 4C, the foamed particle molded body 3 between the side frame portions 23 has a length of 250 mm in the sheet width direction and a length of 10 mm in the front-rear direction. A total of two rectangular slits 4 were formed on the left and right by a cutter knife from a position 400 mm from the front portion (area on the front side 10 mm from the lightening portion 7) and 140 mm from the end portion in the width direction in the width direction. .. The slit 4 was formed on the front side of the two continuous portions 8 sandwiched between the three lightening portions 7. Further, in the central portion of the foamed particle molded body 3, one rectangular auxiliary slit having a length of 210 mm in the sheet width direction and a length of 10 mm in the front-rear direction was formed at a position 360 mm from the front portion by a cutter knife. Each slit was arranged so that the left and right slits and the center slit did not overlap when viewed from the front-rear direction, and were spaced by 30 mm.

Example 4
In the same manner as in Example 1, a sheet core material having no slits was formed. Then, within 10 minutes after molding, as shown in FIG. 4D, the foamed particle molded body 3 between the side frame portions 23 has a length of 250 mm in the sheet width direction and a length of 10 mm in the front-rear direction. A total of two rectangular slits 4 were formed at a position 400 mm from the front portion by a cutter knife, one on each side.

Comparative Example 1
In the same manner as in Example 1, a sheet core material having no slits was formed. No slit was formed in the molded sheet core material.

Comparative Example 2
In the same manner as in Example 1, a sheet core material having no slits was formed. Then, within 10 minutes after molding, a rectangular slit 4 having a length of 1050 mm in the seat width direction and a length of 10 mm in the front-rear direction is formed at a position 360 mm from the front portion by a cutter knife so as to intersect the side frame portion 23. One was formed. The sheet core material was completely divided by the slits 4, and slits were formed so that both ends were not closed.

The sheet core materials of Examples 1 to 3 and Comparative Examples 1 and 2 manufactured under the above conditions were cured in an atmosphere of 60 ° C. for 12 hours and then cooled to obtain the amount of dimensional change in the central portion of the rear side of the sheet core material. The amount of dimensional change at both ends on the rear side of the seat core material was measured. The amount of dimensional change (mm) was measured with a negative value when the measurement position changed to the front side and a positive value when the measurement position changed to the rear side. Then, the difference in the amount of dimensional change (the amount of dimensional change in the central portion-the amount of dimensional change in both ends) was defined as the amount of deformation. The dimension used as the reference for the amount of dimensional change is the dimension of the sheet core material in the design of the measurement position. When the minus of the above deformation amount is large, the difference in the amount of dimensional change between the rear side end portion and the central portion of the seat core material is large, and the rear side central portion is contracted forward, so that the strain is large. It shows that it is.

The following sense of unity was evaluated in the samples in which the sheet core materials of Examples 1 to 4 and Comparative Examples 1 and 2 produced under the above conditions were cured in an atmosphere of 60 ° C. for 12 hours and then cooled.
A: Even if only the end side of the sheet core material is held, there is no problem in handling.
B: If only the end side of the seat core material is held, the seat core material may bend.

From the results in Table 1, the amount of deformation of the sheet core material provided with the slits of Examples 1 to 4 was smaller than the amount of deformation of Comparative Example 1. Further, in Example 2 having a bent structure, the amount of deformation is smaller. In Comparative Example 2, although the amount of deformation of the sheet core material was small, the feeling of unity of the sheet core material was lacking.

From these results, it was confirmed that the sheet core material of the present invention is a sheet core material having excellent dimensional accuracy in which deformation in the front-rear direction is suppressed.

Claims (5)

A vehicle seat core material composed of a thermoplastic resin foamed particle molded body and a frame member embedded in the peripheral portion thereof, and the foamed particle molded body is in a range from the central portion in the front-rear direction to the rear side. It has two or more lightening portions, and penetrates or penetrates a continuous portion between the lightening portions or a region up to 100 mm or less on the front side of the continuous portion along the vehicle width direction of the foamed particle molded product. A sheet core material provided with non-penetrating slits, wherein both ends of the slits in the longitudinal direction are closed. The sheet core material according to claim 1, wherein the opening area of the slit is 5% or less with respect to the projected area of the foamed particle molded body in the top view when the sheet core material is attached. The sheet core material according to claim 1 or 2, wherein the frame member is annular, and the frame member is embedded in a peripheral edge portion of the thermoplastic resin foamed particle molded body. The foamed particle molded product has two or more of the continuous portions, and the foamed particle molded product has the slits in each of the two or more regions up to 100 mm in front of the continuous portion, and the slits are wheels. The sheet core material according to any one of claims 1 to 3, wherein the sheet core material is arranged so as to form an intermittent portion that is intermittent in the width direction. The sheet core material according to claim 4, wherein auxiliary slits are formed in the vertical direction of the foamed particle molded body on the front side of the intermittent portion in parallel with the slits.

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